Inkjet printing is a type of printing that propels drops of ink (also referred to as droplets) onto a medium or substrate, such as paper. The core of an inkjet printer includes one or more print heads (referred to herein as inkjet heads) having multiple ink channels arranged in parallel to discharge droplets of ink. A typical ink channel includes a nozzle, a chamber, and a mechanism for ejecting the ink from the chamber and through the nozzle, which is typically a piezoelectric actuator connected to a diaphragm. To discharge a droplet from an ink channel, a drive circuit provides a drive waveform to the piezoelectric actuator of that ink channel that includes a jetting pulse. In response to the jetting pulse, the piezoelectric actuator generates pressure oscillations inside of the ink channel to push the droplet out of the nozzle. The drive waveforms provided to individual piezoelectric actuators control how droplets are ejected from each of the ink channels.
In an attempt to reduce the size of inkjet heads, the ink channels within the inkjet heads are moved closer together. Also, Drop on Demand (DoD) printing is moving towards higher productivity and quality, which requires small droplet sizes ejected at high jetting frequencies. The print quality delivered by an inkjet head depends on ejection or jetting characteristics, such as droplet velocity, droplet mass (or volume/diameter), jetting direction, etc. Temperature of an inkjet head or the ink in the inkjet head may influence ink viscosity and piezo capacitance, which in turn affects the jetting characteristics. It is therefore desirable to mitigate the effects of temperature variations across an inkjet head to achieve high quality printing.